The cytology of salivary gland neoplasms with globules of extracellular matrix: Case-based review of adenoid cystic carcinoma and its potential mimics.

Fine needle aspiration (FNA) cytology is an important tool for diagnosing salivary gland neoplasms and for guiding clinical management. The classic adenoid cystic carcinoma (AdCC) is a basaloid neoplasm with abundant extracellular matrix. The presence globules of extracellular matrix are quite characteristic of AdCC but not diagnostic. We selected from our files six FNA cases that contained at least some globules of amorphous matrix that are similar to the ones seen in AdCC. The aim of this case-based review is to discuss the pitfalls and some of the common differential diagnoses of AdCC in FNA cytology. By the end of this review, we hope to have shared with the readers the lessons we learned from these cases and to highlight the key criteria needed to make a correct diagnosis of AdCC based on cytomorphology. The importance of considering other entities, in addition to AdCC, whenever a salivary gland FNA presents with globules is emphasized.